Auckland finance analyst Rosemary Fuller suffered swelling to her face after a permanent colour was applied at an Auckland salon last month.

The 42-year-old, who has dyed her hair every nine weeks for about 20 years, said she had not had any adverse reactions till 12 months ago when she had an itchy scalp.

But two days after her April visit she woke to find red liquid all over her pillow. "I had a whole lot of scabs all over my head.

"My GP said the dye had got into the open wounds and that got into my bloodstream which caused the swelling. It was a heck of a mess," she said.

Later that day Ms Fuller and her work colleagues watched in shock as her entire face swelled up sealing shut her eyes. Her doctor gave her strong doses of antihistamines to reduce the puffiness.

Kathy McLauchlan, from Pukerua Bay, said her scalp blistered and her hair fell out in handfuls after applying a semi- permanent colour bought from the supermarket last year. She had the last of it cut out recently and would never colour her hair again, she said.

The chemical most likely to cause adverse reactions is called p- phenylenediamine (PPD). Consumer NZ estimates it is used in two thirds of permanent hair dyes available in supermarkets and pharmacies.

PPD is not on a list of 100 chemicals proposed to be banned from hair dyes being investigated by the Environmental Risk Management Authority. The authority hopes to bring New Zealand into line with European standards.

But the chemical is classified as an extreme sensitiser by the European Commission's scientific committee on consumer products.

It used to be banned in some European countries but is now allowed to make up 6 per cent of a product, the same concentrations that are allowed here.

However, New Zealand manufacturers do not have to say how much of the chemical is in a product.

Dr Crump said PPD was more of a problem with over-the-counter products. He urged users to perform a patch test before every hair colour.